The worrisome rise in diabetes in low- and middle-income countries (LMICs) has resulted from an extraordinary increase in overweight and obesity. LMICs account for 79 per cent of the estimated 463 million persons with diabetes worldwide.
However, until today, there was a paucity of empirical evidence to help doctors and health systems decide which people should be evaluated for diabetes based on their BMI (BMI). "The World Health Organization recommends screening patients age 40 and older with a BMI of 25 kg/m2 and higher for diabetes," says Jennifer Manne-Goehler, MD, ScD, a faculty member at Massachusetts General Hospital's Medical Practice Evaluation Center (MGH)
"However, it's long been assumed that these BMI and age requirements for diabetes screening aren't appropriate in all parts of the world. Our goal was to calculate the relationship between BMI and diabetes risk in a number of lows- and middle-income countries in order to assist resource-constrained health systems in developing the most effective screening programmes for their populations "Manne-Goehler, the senior author of a new study published in The Lancet, agrees.
Manne-Goehler who is an attending physician at Brigham and Women's Hospital's Division of Infectious Diseases and investigators from 57 countries spent five years compiling and utilising existing datasets containing the weight, height, and a diabetes biomarker—either a blood glucose measurement or hemoglobin A1c—of almost 680,000 patients in LMICs.
Link between BMI and diabetes
The study, which was the first of its type, discovered significant geographical disparities in the relationship between BMI and the risk of diabetes. People with a BMI of 23 kg/m2 or higher had a higher risk of diabetes across all LMICs.In various places, the researchers discovered disparities in diabetes risk based on BMI categories.
For example, being overweight or obese increased the risk of diabetes by more than 100 per cent in men and women in Sub-Saharan Africa and East/Southeast Asia. These findings backed up a growing body of evidence from Asia and South Asia that suggests utilising lower BMI thresholds to better identify metabolic risk in these populations.
While the prevalence of diabetes grew as people reached middle age and beyond, the proportion of people with diabetes climbed dramatically in the 35-to-44 age group, as well as among men 25 to 34 years old in Sub-Saharan Africa. "Diagnosing diabetes early in life can help prevent long-term consequences," adds Manne-Goehler.
"Although the results aren't prescriptive," she says, "we hope that policymakers in LMICs will find this evidence valuable as they try to figure out how to invest limited resources to improve diabetes screening for their specific populations."
The study also highlights the value of cross-national collaboration in generating critical evidence for public health guidelines. "When individual countries are evaluating diabetes risk in only one country's survey," Manne-Goehler says, "it's difficult to make relevant high-level global conclusions." For example, the World Health Organization is developing a global strategy dubbed the Global Diabetes Compact to scale up diabetes care. "We believe that our collaboration of many scientists from these 57 countries will assist to inform global optimal diabetes screening techniques," she says.
In a related commentary in The Lancet, Siméon Pierre Choukem, MD, dean of the faculty of Medicine and Pharmaceutical Sciences, University of Dschang, Cameroon, writes, "LMICs now have evidence-based specific answers to the 'Who? When? and How much?' regarding diabetes prevention and screening in relation to BMI." "These findings have substantial public health implications because the true burden of diabetes in LMICs is likely underestimated as a result of current screening criteria, but to what extent is unknown."
The international team of researchers is now investigating how waist circumference, when combined with BMI, can improve the accuracy of diabetes risk assessment, as well as the relationship between behavioural factors such as alcohol, smoking, physical activity, and diet, and diabetes risk in these 57 countries.
The researchers intend to form collaborations in the future that include surveys from high-income nations, allowing for direct comparisons across a broader range of global health settings. "Every country's health-care system must make the best use of its resources to improve the health of its people," says Manne-Goehler.